Modular energy absorbing panels which interlock or snap together to create a resilient underlayment system or “shockpad” are disclosed for example in commonly owned U.S. Pub. No. 2016/0138275. Such shockpads system lie between a foundation or reaction surface and the surface that receives the impact. Examples of reaction surfaces include planar or undulating compacted soil, crushed stone, concrete, asphalt, wood, decking, and other rigid surfaces. Examples of impact receiving surfaces include artificial turf for sports such as golf, football, lacrosse, soccer, lacrosse, baseball, cricket, field hockey and the like. Also included are flooring surfaces such as carpet, vinyl, plastic materials, thermoset materials, wood, steel and composite structures.
Ideally, the interposed underlayment system absorbs and redistributes at least some of the energy applied by an impacting object such as a football helmet or a golf ball through flexure of the underlayment system. In the case of synthetic turf, one desirable feature is for the underlayment system to mimic the response of natural grass during and after impact. Further non-limiting examples of the impacting object include a soccer ball, a baseball, and a lacrosse stick. The behavior of a golf ball before, during and after impact with a playing surface is of particular interest to sports enthusiasts and their governing bodies.
One aspect important to any underlayment system is the ease and cost of installation of the underlayment system. While the addition of a pad or underlayment system complicates the installation of the entire system, it would be desirable to minimize the amount of time, effort, and costs associated with the overall system installation.
U.S. Pub. No. 2106/0138275 describes a modular energy absorbing system comprising a series of individual panels which snap together to create a resilient system which, once installed, improves the performance of the overall turf system. Against this background it would be desirable to reduce the cost, time and effort of system placement at an installation site.
Commercially available flooring products such as Pergo® and other flooring laminates enable component parts of the receiving surface to click or snaps together independently of the underlayment system. In such cases, the underlayment system installation precedes the flooring or cover surface installation. Ideally, it would be desirable to create a system where the underlayment and the impact receiving surface can be installed simultaneously.
In an industrial setting, flooring systems are sometimes provided that absorb forces generated by repeated footfalls. Playground systems also require some means of absorbing energy to reduce the risk of serious injury when a child falls on the surfaces beneath and around playground structures.
In an effort to improve the consistency of the turf and flooring systems, several shockpad systems have been developed and deployed in recent years. The three main categories for of such systems are pour in-place products, rolled goods, and panels.
Pour in place systems are applied in a manner similar to cement or asphalt. Ground crumb rubber is combined with a thermosetting binder and then manipulated using conventional paving equipment. Once cured, these systems compliment the performance of the turf system. Historically, these systems have been prone to variation based on the installed thickness and chemical mixing of the binder and rubber. They are also more prone to breakdown due to several factors. They are permanent and require the use of heavy equipment to install.
Rolled goods are one of the easiest materials to install. Large rolls of foam are unrolled and then either taped or stitched together to create a uniform surface. Rolls are produced from a variety of materials including ground polyurethane foam, ground tires, rubber, cross-linked olefin foams, and expanded polypropylene foam. These materials typically tend to have issues with expansion and contraction under the cover surface and are relatively in-efficient in their ability to absorb energy.
Foam panels, typically made from low density EPP foam with or without formed interlocking sections have also been used. These systems react well to expansion and contraction. However their light weight and low density proves challenging during both installation where they have a tendency to “sail” in the wind.
For synthetic turf golf greens, the shockpad systems which lie below the synthetic turf are typically multi-layered systems. The shockpad typically includes a matrix of fibrous material that is filled with sand. Synthetic turf is laid over the top of the shockpad and then sand is added for balance. These types of systems rely largely relying on the sand to dissipate a large percentage of the incoming energy in a manner similar to natural grass greens such as the Shotstopper® system developed by Synlawn® owned by AstroTurf®. These types of systems may be expensive and the installation process is slow. The system profile is thick. A large volume of sand needs to be worked into the fibrous material. This takes a substantial amount of sand, time, and labor. The ideal system would be inexpensive, low profile, easy to install and duplicate the performance of natural grass upon installation.